CN107269357B

CN107269357B - Exhaust gas aftertreatment system and internal combustion engine

Info

Publication number: CN107269357B
Application number: CN201710208180.6A
Authority: CN
Inventors: A.德林; F.纳纳; P.托舍夫
Original assignee: MAN Energy Solutions SE
Current assignee: MAN Energy Solutions SE
Priority date: 2016-03-31
Filing date: 2017-03-31
Publication date: 2021-07-27
Anticipated expiration: 2037-03-31
Also published as: DE102016205327A1; FI20175254A; NO20170536A1; KR20170113337A; JP6966670B2; CN107269357A; JP2017187035A

Abstract

The invention relates to an exhaust gas aftertreatment system and an internal combustion engine. Exhaust gas aftertreatment system (3), namely an SCR exhaust gas aftertreatment system, of an internal combustion engine, with an SCR catalytic converter (9) accommodated in a reaction chamber (10), with an exhaust gas supply line (8) leading to the reaction chamber (10) and thus to the SCR catalytic converter (9), with an exhaust gas discharge line (11) leading away from the reaction chamber (10) and thus from the SCR catalytic converter (9), with an introduction device (16) assigned to the exhaust gas supply line (8) for introducing a reducing agent, in particular ammonia or a precursor substance of ammonia, into the exhaust gas, with a mixing section (18) provided by the exhaust gas supply line (8) downstream of the introduction device (16) for mixing the exhaust gas with the reducing agent upstream of the reaction chamber (10) or the SCR catalytic converter (9), and with the aid of which the thermal energy of the exhaust gas can be transferred from the exhaust gas downstream of the SCR catalytic converter (9) to the thermal energy of the exhaust gas upstream of the SCR catalytic converter (9) A transducer (25).

Description

Exhaust gas aftertreatment system and internal combustion engine

Technical Field

The present invention relates to an exhaust gas after-treatment system for an internal combustion engine. The invention further relates to an internal combustion engine with an exhaust gas aftertreatment system.

Background

Nitrogen oxides are produced during the combustion of stationary internal combustion engines, for example used in power stations, and during the combustion of non-stationary internal combustion engines, for example used on ships, wherein these nitrogen oxides are usually produced during the combustion of sulphur-containing fossil fuels, such as coal, bituminous coal, crude oil, heavy fuel oil or diesel. For this reason, these internal combustion engines are equipped with exhaust gas aftertreatment systems for cleaning, in particular denitrification, of the exhaust gases leaving the internal combustion engine.

In order to reduce the nitrogen oxides in the exhaust gas, so-called SCR catalytic converters are mainly used in exhaust gas aftertreatment systems known from practice. In an SCR catalytic converterIn which a selective catalytic reduction of nitrogen oxides takes place, in which ammonia (NH) is required₃) As a reducing agent for the reduction of nitrogen oxides. Thus, ammonia or a precursor substance of ammonia, such as for example urea, is introduced into the exhaust gas in liquid form upstream of the SCR catalytic converter, wherein the ammonia or the precursor substance of ammonia is mixed with the exhaust gas upstream of the SCR catalytic converter. For this purpose, a mixing section is provided between the introduction of ammonia or the introduction of a precursor substance for ammonia and the SCR catalytic converter according to practice.

Although successful exhaust gas aftertreatment, in particular the reduction of nitrogen oxides, has been possible with exhaust gas aftertreatment systems known from practice which comprise SCR catalytic converters, there is a need for further improvements of exhaust gas aftertreatment systems. In particular, there is a need for: effective exhaust gas aftertreatment is made possible with a compact design of these exhaust gas aftertreatment systems.

Starting from this point, the object of the invention is based on: an exhaust gas aftertreatment system for a new type of internal combustion engine and an internal combustion engine with such an exhaust gas aftertreatment system are created.

Disclosure of Invention

This object is solved by an exhaust gas aftertreatment system for an internal combustion engine as described below. An exhaust gas aftertreatment system of an internal combustion engine, namely an SCR exhaust gas aftertreatment system of an internal combustion engine, comprising: an SCR catalytic converter received in the reaction chamber, an exhaust gas supply line leading to the reaction chamber and thus to the SCR catalytic converter, an exhaust gas discharge line leading away from the reaction chamber and thus from the SCR catalytic converter, an introduction device dosed to the exhaust gas supply line for introducing a reducing agent, in particular ammonia or a precursor substance of ammonia, into the exhaust gas, and a mixing section provided by the exhaust gas supply line downstream of the introduction device for mixing the exhaust gas with the reducing agent upstream of the reaction chamber or the SCR catalytic converter. At least one blow-off device is positioned within the reaction chamber for purging the SCR catalytic converter.

The exhaust gas aftertreatment system according to the invention comprises a heat exchanger with the aid of which the thermal energy of the exhaust gas can be transferred from the exhaust gas downstream of the SCR catalytic converter to the exhaust gas upstream of the SCR catalytic converter. By means of the heat exchanger, the exhaust gas temperature can be set to a level that is optimal for the SCR process. The thermal energy released during the exothermic reaction of the SCR treatment and present in the exhaust gas downstream of the SCR catalytic converter is transferred to the exhaust gas upstream of the SCR catalytic converter. For this reason, by increasing the temperature upstream of the SCR catalytic converter, effective exhaust gas aftertreatment is possible.

According to a further advantageous development of the invention, the exhaust gas supply line and the exhaust gas discharge line are connected on a common side of the reaction chamber, wherein one of these exhaust gas lines encloses the other of these exhaust gas lines in the section forming the heat exchanger. This further development allows an effective exhaust gas aftertreatment with a compact and simple design of the exhaust gas aftertreatment system.

Preferably, adjacent to the side of the reaction chamber to which the two exhaust gas lines are connected, the exhaust gas discharge line partially surrounds the exhaust gas supply line on the outside, wherein a section of the exhaust gas supply line around which the exhaust gas circulates upstream of the SCR catalytic converter, viewed in the flow direction of the exhaust gas supply line, is surrounded by the exhaust gas discharge line on the one hand and continues in the reaction chamber on the other hand. This further development allows an effective exhaust gas aftertreatment with a particularly compact and simple exhaust gas aftertreatment system design. In particular, deposits on the walls of the exhaust gas supply line can be avoided.

According to a further advantageous development of the invention, the ratio between the length of the SCR catalytic converter and the length of the section of the exhaust gas supply line around which the exhaust gas circulates upstream of the SCR catalytic converter amounts to at least 1:5, preferably at least 1:8, particularly preferably at least 1: 10. This further development allows effective exhaust gas aftertreatment with a particularly simple and compact exhaust gas aftertreatment system design.

The further improvement lies in that: the heat transfer is increased by increasing the pressure level of the exhaust gas. Advantageously, the absolute pressure is increased to at least 0.2MPa, advantageously to at least 0.3MPa, most advantageously to at least 0.4 MPa. In order to be able to omit a separate compressor for increasing the exhaust gas pressure, it is appropriate: the heat exchanger and thus also the SCR reactor are arranged upstream of the at least one exhaust gas turbine.

The internal combustion engine according to the invention has an exhaust gas aftertreatment system as described above.

Drawings

Preferred further developments of the invention are derived from the dependent claims and the following description. Exemplary embodiments of the present invention will be described in more detail by the following contents, but are not limited thereto. Shown in the attached drawings:

FIG. 1: a schematic perspective view of an internal combustion engine with an exhaust gas aftertreatment system according to the invention;

FIG. 2: details of the exhaust aftertreatment system of fig. 1.

Detailed Description

The present invention relates to an exhaust gas after-treatment system for an internal combustion engine, for example, an exhaust gas after-treatment system for a stationary internal combustion engine in a power plant or an exhaust gas after-treatment system for a non-stationary internal combustion engine used on a ship. In particular, the exhaust gas aftertreatment system is used on diesel engines of ships operating on heavy fuel oil.

Fig. 1 shows an arrangement of an exhaust-gas-charged internal combustion engine 1 with an exhaust-gas turbocharging system 2 and an exhaust-gas aftertreatment system 3. The internal combustion engine 1 may be a non-stationary internal combustion engine or a stationary internal combustion engine, in particular an internal combustion engine of a marine vessel which is operated non-stationary. The exhaust gases leaving the cylinders of the combustion engine 1 are utilized in the exhaust gas charging system 2 in order to extract mechanical energy from the thermal energy of the exhaust gases for compressing the charge air to be supplied to the combustion engine 1.

Accordingly, fig. 1 shows an internal combustion engine 1 with an exhaust-gas turbocharging system 2 which comprises a plurality of exhaust-gas turbochargers, namely a first exhaust-gas turbocharger 4 on the high-pressure side and a second exhaust-gas turbocharger 5 on the low-pressure side. The exhaust gases leaving the cylinders of the internal combustion engine 1 initially flow through the high-pressure turbine 6 of the first exhaust-gas turbocharger 1 and expand therein, wherein the energy extracted in the process is utilized in the high-pressure compressor of the first exhaust-gas turbocharger 4 in order to compress the charge air. The second exhaust-gas turbocharger 5 is arranged downstream of the first turbocharger 4, viewed in the flow direction of the exhaust gases, through which the exhaust gases which have passed through the high-pressure turbine 6 of the first exhaust-gas turbocharger 4 are led, i.e. through the low-pressure turbine 7 of the second exhaust-gas turbocharger 5. In the low-pressure turbine 7 of the second exhaust-gas turbocharger 5, the exhaust gases expand further and the energy extracted in the process is utilized in the low-pressure compressor of the second exhaust-gas turbocharger 5, so that the charge air to be supplied to the cylinders of the internal combustion engine 1 is likewise compressed.

In addition to the exhaust gas charging system 2, which contains the exhaust gas turbochargers 4 and 5, the internal combustion engine 1 also contains an exhaust gas aftertreatment system 3, which is an SCR exhaust gas aftertreatment system. The SCR exhaust gas aftertreatment system 3 is connected between the high-pressure turbine 6 and the low-pressure turbine 7 of the first compressor 5, so that the exhaust gas leaving the high-pressure turbine 6 of the first exhaust gas turbocharger 4 can be led through the SCR exhaust gas aftertreatment system 3 before it reaches the region of the low-pressure turbine 7 of the second exhaust gas turbocharger 5. Thus, the heat exchanger operates at an elevated pressure level, thus improving heat transfer.

Fig. 1 shows an exhaust gas supply line 8, by means of which exhaust gas flowing out of the high-pressure turbine 6 of the first exhaust gas turbocharger 4 can be guided in the direction of an SCR catalytic converter 9 (see fig. 2) arranged in a reaction chamber 10.

Fig. 1 furthermore shows an exhaust gas discharge line 11 for discharging the exhaust gas from the SCR catalytic converter 9 in the direction of the low-pressure turbine 7 of the second exhaust gas turbocharger 5.

The exhaust gases flow from the low-pressure turbine 7 via a line 21, in particular into the open air.

The exhaust gas supply line 8 leading to the reaction chamber 10 and thus to the SCR catalytic converter 9 positioned in the reaction chamber 10 is coupled with the exhaust gas discharge line 11 leading away from the reaction chamber 10 and thus from the SCR catalytic converter 9 by a bypass 12, in which a shut-off element 13 is incorporated. With shut-off element 13 closed, bypass 12 is closed so that no exhaust gas can flow through the bypass. Conversely, in particular when the shut-off element 13 is opened, exhaust gases can flow through the bypass 12, i.e. over the reaction chamber 10 and correspondingly over the SCR catalytic converter 9 located in the reaction chamber 10.

Fig. 2 illustrates the flow of exhaust gases through the exhaust gas aftertreatment system 3 with the bypass 12 closed by means of the shut-off element 13 by means of an arrow 14, wherein it is apparent from fig. 2 that: the exhaust gas supply line 8 opens with a downstream end 15 into the reaction chamber 10, wherein the exhaust gas in the region of this end 15 of the exhaust gas supply line 8 is subjected to a flow deflection of approximately 180 °, wherein the exhaust gas is guided through the SCR catalytic converter 9 after the flow deflection.

The exhaust gas supply line 8 of the exhaust gas aftertreatment system 3 is equipped with an introduction device 16, by means of which a reducing agent, in particular ammonia or a precursor substance of ammonia, can be introduced into the exhaust gas flow, which is required in order to convert the nitrogen oxides of the exhaust gas in a defined manner in the region of the SCR catalytic converter 9. This introduction device 16 of the exhaust gas aftertreatment system 3 is preferably a nozzle, through which ammonia or ammonia precursors are injected into the exhaust gas flow in the exhaust gas supply line 8. Fig. 2 illustrates with a cone 17 that the reducing agent is injected into the exhaust gas in the region of the exhaust gas supply line 8. The section of the exhaust gas aftertreatment system 3 which is located downstream of the introduction device 16 and upstream of the SCR catalytic converter 9, viewed in the flow direction of the exhaust gas, is described as a mixing section. In particular, the exhaust gas supply line 8 provides downstream of the introduction device 16 a mixing section 18 in which the exhaust gas can be mixed with the reducing agent upstream of the SCR catalytic converter 9.

The exhaust gas supply line 8 opens into the reaction chamber 10 at a downstream end 15. This downstream end 15 of the exhaust gas supply line 8 is provided with a baffle element 20 which is displaceable relative to the downstream end 15 of the exhaust gas supply line 8. In the exemplary embodiment shown, the baffle element 20 is linearly displaceable relative to said end 15 of the exhaust gas supply line 8 leading into the reaction chamber 10.

The baffle element 20 may be displaced relative to the downstream end 15 of the exhaust gas supply line 8, thereby closing the exhaust gas supply line 8 at the downstream end 15 or opening the exhaust gas supply line 8 at the downstream end 15. In particular when the baffle element 20 closes the exhaust gas supply line 8 at the downstream end 15, the shut-off element 13 of the bypass 12 is preferably opened in order then to guide the exhaust gas completely over the SCR catalytic converter 9 or the reaction chamber 10 receiving the SCR catalytic converter 9.

The shut-off element 13 of the bypass 12 can be completely closed or at least partially open, in particular when the baffle element 20 opens the downstream end 15 of the exhaust gas supply line 8. In particular when the baffle element 20 opens the downstream end 15 of the exhaust gas supply line 8, the relative position of the baffle element 20 with respect to the downstream end 15 of the exhaust gas supply line 8 depends in particular on the exhaust gas mass flow through the exhaust gas supply line 8 and/or on the exhaust gas temperature of the exhaust gas in the exhaust gas supply line 8 and/or on the amount of reducing agent introduced into the exhaust gas flow by the introduction device 16.

The further function of the baffle element 20 with the downstream end 15 of the exhaust gas supply line 8 open is: any droplets of liquid reducing agent present in the exhaust gas flow reach the baffle element where they are intercepted and atomized in order to avoid these droplets of liquid reducing agent reaching the area of the SCR catalytic converter 9. In the case of an open downstream end 15, it is possible, in particular, to determine the relative position of the baffle element 20 with respect to the downstream end 15 of the exhaust gas supply line 8: the exhaust gases deflected in the region of the baffle element 20 in the region of the downstream end 15 of the exhaust gas supply line 8 are guided or deflected more in the direction of the radially inner section or in the direction of the radially outer section of the SCR catalytic converter 9.

According to a preferred embodiment, the exhaust gas supply line 8 is flared in the region of the downstream end 15, forming a diffuser. Because of this, the flow cross section of the exhaust gas supply line 8 increases in the region of the downstream end 15, wherein, as is particularly evident from fig. 2, it is possible to provide: the flow cross section of the exhaust gas supply line 8 begins to become smaller, seen in the flow direction of the exhaust gas, upstream of the downstream end 15 thereof. Correspondingly, fig. 2 shows that the flow cross section of the exhaust gas supply line 8 initially approximately does not change, but then begins to taper and finally expands in the region of the downstream end 15, downstream of the introduction device 16 for the reducing agent, as viewed in the flow direction of the exhaust gas. In this case, this enlargement of the flow cross section at the downstream end 15 of the exhaust gas supply line 8 is preferably effected by a shorter section of the exhaust gas supply line 8 and not by the section which, before the downstream end 15, begins to taper via its exhaust gas supply line 8. In that axial position of the exhaust gas supply line 8 in which the flow direction of the exhaust gas supply line begins to taper, the SCR catalytic converter 9 is arranged radially outside the exhaust gas supply line 8.

Preferably, the baffle element 20 is curved, preferably bell-shaped on the side 22 facing the exhaust gas supply line 8, forming a flow guide for the exhaust gases. The side of the baffle element 20 facing the downstream end 15 of the exhaust gas supply line 8 has a shorter distance to the downstream end 15 of the exhaust gas supply line 8 on a radially inner section of the baffle element 20 than on a radially outer section of the baffle element 20. The baffle element 20 is therefore drawn or bent in the center in the direction of the downstream end 15 of the exhaust gas supply line 8 against the flow direction of the exhaust gas.

As is particularly evident from fig. 2, the exhaust gas supply line 8 and the exhaust gas discharge line 11 are connected together on a first side 24 of the reaction chamber 10 or lead or extend into the reaction chamber 10 starting from this common side 24.

Here, the exhaust gas supply line 8 extends into the reaction chamber 10 in such a way that the downstream end 15 of the exhaust gas supply line 8 is located adjacent to a second side 23 of the reaction chamber 10 located opposite to a first side 24 of the reaction chamber 10, while the exhaust gas discharge line 11 opens into the reaction chamber 10 at the first side 24. The exhaust gas supplied in through the exhaust gas supply line 8 is thus deflected by approximately 180 ° in the region of the second side 23 of the reaction chamber 10 located opposite the downstream end 15 of the exhaust gas supply line 8, then flows through the SCR catalytic converter 9 and subsequently enters through the second side 24 into the region of the exhaust gas discharge line 11. The wall 19 of the reaction chamber 10, which is preferably circular in cross-section, extends between a first side 24 of the reaction chamber 10 and a second side 23 of the reaction chamber 10, which is located opposite.

According to the invention, the exhaust gas aftertreatment system 3 comprises a heat exchanger 25 with the aid of which the thermal energy of the exhaust gas can be transferred from the exhaust gas downstream of the SCR catalytic converter 9 to the exhaust gas upstream of the SCR catalytic converter 9. The thermal energy released during the exothermic reaction of the SCR process and present in the exhaust gas downstream of the SCR catalytic converter 9 is transferred to the exhaust gas upstream of the SCR catalytic converter 9. Thus, the exhaust gas temperature can be set to a temperature optimal for the SCR treatment, and effective exhaust gas aftertreatment is made possible.

The exhaust gas supply line 8 and the exhaust gas discharge line 11 are jointly connected on a first side 24 of the reaction chamber 10, wherein one of the exhaust gas lines 8, 11 encloses the other of the exhaust gas lines 8, 11 in a section forming the heat exchanger 25. In the shown preferred exemplary embodiment, adjacent to the first side 24 of the reaction chamber 10, to which the two exhaust gas lines 8, 11 are connected, the exhaust gas discharge line 11 partially, preferably concentrically, surrounds the exhaust gas supply line 8 on the outside.

Thus, with a compact and simple design of the exhaust gas aftertreatment system 3, the thermal energy present in the exhaust gas downstream of the SCR catalytic converter can be reliably transferred to the exhaust gas upstream of the SCR catalytic converter 9. There is no risk of deposits forming in the region of the exhaust gas supply line 8.

The exhaust gas discharge line 11 surrounds the exhaust gas supply line 8 in the region of the mixing section 18. The section of the exhaust gas supply line 8 which is surrounded by a section of the exhaust gas discharge line 11, viewed in the flow direction of the exhaust gas supply line 8, is positioned downstream of the introduction device 16 for introducing the reducing agent into the exhaust gas and, correspondingly, in the region of the mixing section 18.

The ratio, viewed in the exhaust gas flow direction, between the length l1 of the SCR catalytic converter 9 and the length l2 of the section of the exhaust gas supply line 8 around which the exhaust gas circulates upstream of the SCR catalytic converter 9 amounts to at least 1:5, preferably at least 1:8, particularly preferably at least 1: 10. Therefore, the thermal energy present in the exhaust gas downstream of the SCR catalytic converter 9 can be reliably transferred to the exhaust gas upstream of the SCR catalytic converter 9.

The section of the exhaust gas supply line 8 around which the exhaust gas circulates upstream of the SCR catalytic converter 9 is, on the one hand, surrounded by the exhaust gas discharge line 11 and, on the other hand, continues in the reaction chamber 10. The length l2 of the section of the exhaust gas supply line 8 around which the exhaust gas circulates upstream of the SCR catalytic converter is therefore formed by the length l21 of the partial section surrounded by the exhaust gas discharge line 11 and the length l22 of the partial section continuing within the reaction chamber 10.

The reaction chamber 10 and/or the exhaust gas discharge line 11 and/or the exhaust gas supply line 8 are profiled in such a way that: the flow cross section for the exhaust gas, viewed in the flow direction of the exhaust gas, tapers downstream of the SCR catalytic converter 9. In the exemplary embodiment, this is ensured by the conical shape of the first side 24 of the catalytic converter 10. By such a tapering of the flow cross section, the defined flow rate is set in the section of the exhaust gas discharge line 11 forming the heat exchanger 25 which surrounds the exhaust gas supply line 8 on the outside, so that a particularly efficient transfer of thermal energy to the exhaust gas upstream of the SCR catalytic converter 9, which is present in the exhaust gas downstream of the SCR catalytic converter, is achieved.

In the case of the internal combustion engine 1 of fig. 1, the exhaust gas aftertreatment system 3 is positioned vertically upstream of the exhaust gas charging system 2. Access to the cylinders of the internal combustion engine 1 is free, however, the accessibility of the exhaust gas turbochargers 4 and 5 is limited. However, the reaction chamber 10 can be simply disassembled when maintenance operations on the turbochargers 4, 6 become necessary. A horizontal arrangement in which the exhaust gas aftertreatment system 3 is tilted by 90 ° close to the exhaust gas charging system 2 is also possible in comparison with the vertical arrangement of the exhaust gas aftertreatment system 3 upstream of the exhaust gas charging system 2 shown in fig. 1, wherein, however, in the case of such a horizontal arrangement, the length of the arrangement increases. However, the internal combustion engine 1 and the exhaust gas charging system 2 can then be used for maintenance work without any restrictions, without the need to disassemble and assemble the reaction chamber 10.

Particularly preferably, the invention is used with a two-stage supercharged four-stroke engine or with a two-stroke engine in which the exhaust gas temperature upstream of the SCR catalytic converter is less than 300 ℃. In these engines, the exhaust gas temperature can be adjusted to a level optimal for SCR treatment using the present invention.

List of reference numerals

1 internal combustion engine

2 exhaust gas supercharging system

3 exhaust gas aftertreatment system

4 exhaust gas turbocharger

5 exhaust gas turbocharger

6 high-pressure turbine

7 low-pressure turbine

8 waste gas supply line

9 SCR catalytic converter

10 reaction chamber

11 exhaust gas discharge line

12 bypass

13 cutting element

14 exhaust gas guide

15 terminal

16 introducing device

17 spray cone

18 mixing section

19 wall

20 baffle plate element

21 pipeline

Side 22

Side 23

Side 24

25 heat exchanger

Claims

1. An exhaust gas aftertreatment system (3) of an internal combustion engine with an SCR catalytic converter (9) received in a reaction chamber (10), with an exhaust gas supply line (8) leading to the reaction chamber (10) and thus to the SCR catalytic converter (9), with an exhaust gas discharge line (11) leading away from the reaction chamber (10) and thus from the SCR catalytic converter (9), with an introduction device (16) assigned to the exhaust gas supply line (8) for introducing a reducing agent into the exhaust gas, and with a mixing section (18) provided by the exhaust gas supply line (8) downstream of the introduction device (16) for mixing the exhaust gas with the reducing agent upstream of the reaction chamber (10) or the SCR catalytic converter (9), characterized in that: at least one baffle element (20) is positioned within the reaction chamber (10) at the downstream end (15) of the exhaust gas supply line (8), where said exhaust gas supply line opens into the reaction chamber (10), and which is displaceable relative to the downstream end (15) of the exhaust gas supply line (8) so as to close the exhaust gas supply line at the downstream end or open the exhaust gas supply line at the downstream end, wherein when said baffle element (20) opens the downstream end (15) of the exhaust gas supply line (8), droplets of liquid reducing agent present in the exhaust gas flow are intercepted and atomized at the baffle element so as to avoid these droplets of liquid reducing agent from entering the region of the SCR catalytic converter (9).

2. The exhaust aftertreatment system of claim 1, wherein: the pressure in the heat exchanger reaches at least 0.2MPa abs.

3. The exhaust aftertreatment system of claim 2, wherein: the pressure in the heat exchanger reaches at least 0.3MPa abs.

4. The exhaust aftertreatment system of claim 3, wherein: the pressure in the heat exchanger reaches at least 0.4MPa abs.

5. The exhaust aftertreatment system of claim 1, wherein: the heat exchanger is arranged upstream of at least one turbine of the exhaust-gas-supercharged combustion engine.

6. The exhaust aftertreatment system of claim 1, wherein: the exhaust gas supply line (8) and the exhaust gas discharge line (11) are jointly connected to one side (24) of the reaction chamber (10), wherein one of the exhaust gas lines surrounds the other of the exhaust gas lines in the section forming the heat exchanger (25).

7. The exhaust aftertreatment system of claim 2, wherein: adjacent to one side (24) of the reaction chamber (10) to which the two exhaust gas lines (8, 11) are partially connected on the outside, the exhaust gas discharge line (11) surrounds the exhaust gas supply line (8).

8. The exhaust aftertreatment system of claim 7, wherein: the exhaust gas discharge line (11) surrounds the exhaust gas supply line (8) concentrically in part.

9. The exhaust aftertreatment system of claim 8, wherein: the exhaust gas discharge line (11) surrounds the exhaust gas supply line (8) on the outside in the region of the mixing section (18).

10. The exhaust aftertreatment system of any one of claims 7-9, wherein: the section of the exhaust gas supply line (8) which is surrounded by the section of the exhaust gas discharge line (11) is positioned downstream of an introduction device (16) for introducing a reducing agent into the exhaust gas, as seen in the flow direction of the exhaust gas supply line (8).

11. The exhaust aftertreatment system of any one of claims 7-9, wherein: the ratio between the length of the SCR catalytic converter (9) and the length of the section of the exhaust gas supply line (8) around which the exhaust gas circulates upstream of the SCR catalytic converter (9) amounts to at least 1: 5.

12. The exhaust aftertreatment system of any one of claims 7-9, wherein: the ratio between the length of the SCR catalytic converter (9) and the length of the section of the exhaust gas supply line (8) around which the exhaust gas circulates upstream of the SCR catalytic converter (9) amounts to at least 1: 8.

13. The exhaust aftertreatment system of any one of claims 7-9, wherein: the ratio between the length of the SCR catalytic converter (9) and the length of the section of the exhaust gas supply line (8) around which the exhaust gas circulates upstream of the SCR catalytic converter (9) amounts to at least 1: 10.

14. The exhaust aftertreatment system of claim 11, wherein: the section of the exhaust gas supply line (8) around which the exhaust gas circulates upstream of the SCR catalytic converter (9) is surrounded on the one hand by the exhaust gas discharge line (11) and continues in the reaction chamber (10) on the other hand.

15. The exhaust aftertreatment system of any one of claims 7-9, wherein: the reaction chamber (10) and/or the exhaust gas discharge line (11) and/or the exhaust gas supply line (8) are profiled in such a way that the flow cross section for the exhaust gas, viewed in the flow direction of the exhaust gas, tapers downstream of the SCR catalytic converter (9).

16. An internal combustion engine (1) with an exhaust gas aftertreatment system (3) according to any one of claims 1 to 15.

17. The internal combustion engine of claim 16, wherein: the internal combustion engine comprises an exhaust gas charging system (2) with at least one exhaust gas turbocharger, wherein an exhaust gas aftertreatment system (3) is connected between a cylinder of the internal combustion engine and the exhaust gas charging system (2).

18. The internal combustion engine of claim 16, wherein: the internal combustion engine comprises a multistage exhaust gas charging system with a first exhaust gas turbocharger (4) comprising a high-pressure turbine (6) and a second exhaust gas turbocharger (5) comprising a low-pressure turbine (7), wherein an exhaust gas aftertreatment system (3) is connected between the high-pressure turbine (6) and the low-pressure turbine (7).

19. The internal combustion engine of claim 16, wherein: the internal combustion engine operates on diesel or on a heavy fuel petroleum fuel.